[Ag(TO)~2]ClO~4.H~2O was prepared by mixing the aqueous solution of 1, 2, 4-triazol-5-one (TO) and silver perchlorate. It was characterized by X-ray diffraction, TG-DTG, and IR measurement. The crystal is triclinic, space group P1 with a=0.533(1)nm, b=0.938(1)nm, c=1.220(1)nm; α=88.02(1)ⅲ, β=79.50(1)ⅲ, γ=82.86(1)ⅲ; V=0.5953(8) nm^3, Z=2, R is 0.0281. The silver atom has a slightly bent linear coordination geometry with two nitrogen atoms.

Key words: SILVER COMPLEX, CRYSTAL STRUCTURE, PYRRODIAZOLE P, X- RAY DIFFRACTION ANALYSIS